On Mon, Jan 22, 2024, Binbin Wu wrote: > + if (this_cpu_has(X86_FEATURE_LA57) && read_cr4() & X86_CR4_LA57) Checking for feature support seems superfluous, e.g. LA57 should never be set if it's unsupported. Then you can do lam_mask = is_la57_enabled() ? LAM57_MASK : LAM48_MASK; > + lam_mask = LAM57_MASK; > + > + vaddr = alloc_vpage(); > + install_page(current_page_table(), virt_to_phys(alloc_page()), vaddr); > + /* > + * Since the stack memory address in KUT doesn't follow kernel address > + * space partition rule, reuse the memory address for descriptor and > + * the target address in the descriptor of invvpid. > + */ > + operand = (struct invvpid_operand *)vaddr; Why bother backing the virtual address? MOV needs a valid translation, but INVVPID does not (ditto for INVLPG and INVPCID, though it might be simpler and easier to just use the allocated address for those). > + operand->vpid = 0xffff; > + operand->gla = (u64)vaddr; > + operand = (struct invvpid_operand *)set_la_non_canonical((u64)operand, > + lam_mask); > + fault = test_for_exception(GP_VECTOR, ds_invvpid, operand); > + report(!fault, "INVVPID (LAM on): tagged operand");
